GuidesMultiple servers
The safety checks
At each start, ferryd makes sure that no other server uses its data directory or its prefix.
Lock. Does another ferryd use this data directory?
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One server for each data directory
ferryd holds a lock on <data-dir>/ferryd.lock.
Error: another ferryd is already running with data directory /var/lib/ferryOne data directory for each prefix
At its first start, a server writes two things on the marker volume <prefix>-owner: its identity (<data-dir>/instance_id) and its data directory. After that, a server with another data directory refuses the name prefix.
Error: Docker resources with prefix 'ferry' belong to another Ferry server (data dir /var/lib/ferry). Run this server with a different --name-prefix, stop the other server, or pass --take-over to adopt the resources (the other server's containers will then be managed — and possibly removed — by this one).An empty data directory
The server also refuses to start if its data directory is empty and no marker explains the containers under its prefix.
Error: found 3 Docker container(s) with prefix 'ferry' that this (empty) data dir /home/you/projects/ferry-data doesn't know. They probably belong to another Ferry server. Run this server with a different --name-prefix, …This check catches a common mistake: you start ferryd from another directory, with the default ./ferry-data.
Server options describes --name-prefix, --take-over and the other options.